When a current flows through a coil provided in a stator of a rotary electric machine, the coil generates heat to increase the temperature of the stator. If the temperature of the stator becomes equal to or higher than predetermined heat resistant temperature, components of the stator may be damaged by the heat. Therefore, when the detected temperature of the temperature sensor that is provided in the coil is equal to or higher than predetermined temperature, the current supplied to the coil is interrupted or suppressed to prevent the temperature increase of the stator.
Some of the rotary electric machines supplied with AC power include a neutral point that connects coil ends of respective phases, and temperature of the neutral line in an on-vehicle rotary electric machine is detected. As an example, Patent Literature 1 proposes a rotary electric machine, a temperature sensor of which is more easily replaced when a temperature detection device is broken down.